Marking device, method and apparatus for the production thereof and a method for reading a marking device of this type

ABSTRACT

The invention relates to a marking device ( 1, 11 ) for the identification of objects with a coding of regions ( 4, 5, 13 ) with different magnetic properties. The marking device is characterized in that magnetic regions ( 4, 5, 13 ) are so magnetically biased that their hysteresis loops ( 7, 8, 15 ) are shifted on the field strength axis (H) relative to the magnetization axis (M).  
     The invention relates further to a method and an apparatus for producing such a marking device as well as to a method of reading such a marking device.

[0001] The invention relates to a marking device for the identification of objects, with a coding of regions with different magnetic characteristics. It relates further to a method and apparatus for making it as well as to a method for reading such a marking device.

[0002] For the marking and thus individual correlation and verification of check cards, credit cards, access cards, electronic keys or the like, a number of magnetic codings are used, and mainly in the form of a so-called magnetic strip. For the coding a permanent magnetic layer is selectively, i.e. regionally, so magnetized that regions of different magnetization result, whereby in the sense of the present description, although nonmagnetized regions, i.e. regions of zero magnetization, are included. With corresponding field sensors, the magnetic signature or cording can be determined and processing for the respective purpose can be carried out.

[0003] There are numerous proposals for the formation of magnetic strips. In U.S. Pat. No. 4,650,978, the naturally occurring random variations of the magnetic characteristics of the magnetic strip, having their origins in the variations in coercivity, granularity, layer thickness, surface contour and especially in random variations in the hysteresis loop and other magnetic histories determining same are used. Similar are the codings in the methods according to U.S. Pat. No. 5,616,904 and U.S. Pat. No. 4,837,826. The magnetic structure is thus digitized in a suitable form and used to identify the object. It is a drawback that the magnetic strips can be manipulated relatively simply and are not resistant to external magnetic fields.

[0004] In U.S. Pat. Nos. 5,480,658 and 5,972,438 magnetic strips are described in which magnetic particles are incorporated in a binder, whereby the magnetic strips each have two layers of different coercivities. Also the magnetic strips of U.S. Pat. No. 5,177,344 have magnetic particles in a binder matrix whereby the magnetic particles are so influenced by the application of an external magnetic field that they yield magnetic regions of different characteristics. These types of magnetic strips have the drawback that the magnetic structure can be subsequently altered by heating of the binder and newly orienting the magnetic particles by an external magnetic field. In the magnetic strips of U.S. Pat. No. 5,365,586 a number of microcrystalline structures are arranged in a random grid. The magnetic strips are thus subjected to saturation magnetization, whereby the remanent noise is read out and used for identification. These magnetic strips as well are capable of being influenced by external manipulations.

[0005] In U.S. Pat. No. 5,254,843, conventionally written magnetic bands and strips have random variations in time sequence of flux changes which are used for identification of the respective object. Here as well the random structure, upon identification, can easily be reproduced. Aside from this, the method requires a randomness of the variations in time which, especially in the case of machine writing, cannot be taken for granted.

[0006] In the PCT/EP99/08433, which was not published prior to this, a marking device is proposed in which the coding has a magnetic base layer and a magnetic coding layer which so cooperate that over the extent of the base layer and the coding layer, there are regions with nonparallel or antiparallel magnetic coupling. In this case use is made of the effect of magnetic interlayer coupling. The marking device has the advantage of a highly characteristic property distinguishing from the usual magnetic marking that upon the application of an external magnetic field while the nonparallel or antiparallel coupling is broken by the influence of a saturation magnetic field, the original magnetization is restored after the removal of the external magnetic field. The coding can thus not be extinguished by external magnetic fields. In addition the effect can be used, for example, in the case of magnetic codings which weaken and are even lost as a result of long storage time, to reactivate them in that they are exposed to a saturation magnetic field.

[0007] It is the object of the invention to provide a marking device of the type mentioned at the outset so that the coding is permanent, difficult to manipulate and insensitive to external influences. It should, in addition, enable a verification test without data connection to an external computer. A further object is to provide a method and apparatus for producing such a marking device.

[0008] The first part of this object is achieved in that magnetic regions are so mechanically biased that their hysteresis loops are shifted along the field strength axis with respect to the symmetrical course to the magnetization axis. The influencing of such a magnetic bias, after the completion of manufacture can only take place by application of high field strengths with simultaneous heating above critical Néel temperature. Thus high security against manipulation is ensured. Inadvertent alteration or erasure of the stored data is not possible. By selection of suitable antiferromagnetic materials, the critical Néel temperature can be selected to be so high that a manipulation without destruction of the stored information or of the total system is practically not possible.

[0009] By contrast, the invention opens the possibility of testing of marking devices by combined local reading of the remanent distribution of the magnetization and the distribution of the saturation magnetization. Thus a reliable distinction can be made as to whether one is dealing with the original structure or with a simulation of the magnetic structure. The verification test can be effected mechanically and can be read out without control by a person. An external data connection for verification is not required. As a result, the reading device can be economical and compact, being fabricated using conventional magnetic reading technology.

[0010] Basically it is possible that regions of magnetic bias can be spaced apart. Then the intervening regions can be unmagnetized and of zero magnetization, or can be so magnetized that they are not biased. Alternatively or in combination therewith, regions with a magnetic bias can be provided which have differently shifted hysteresis loops and/or different preferred directions of the magnetic bias. This can apply especially to regions of magnetic bias according to strength and/or direction of different remanences. To the extent regions with magnetic bias directly bound one another or bound one another only with slight spacings, the respective neighboring regions should have differently shifted hysteresis loops and/or different preferred directions of the bias.

[0011] The magnetic stress in the aforedescribed sense, can be produced especially in that at least one antiferromagnetic first layer and, thereover, at least one ferromagnetic or ferrimagnetic, especially soft magnetic, intermediate layer are applied and that by the effect of a magnetic field, regions with magnetic bias are produced which effect a shifting to the hysteresis lip on the field strength axis. The effect of the magnetic field appears preferably already in the generation of the first and second layers to the extent that a magnetic field effect is not provided in the subsequently described special processes, first after the production of the first and second layers.

[0012] The first layer can extend over a plurality of mutually and adjoining regions with magnetic bias. To the extent that the coding involves regions without a first layer, the second layer can also extend over these regions.

[0013] The antiferromagnetic first layer can be composed of an intrinsically antiferromagnetic material like, for example, Mn as well as NiO, MnFe or MnNi with preferably a ratio of 50:50 atomic parts, MnIr preferably with an atomic part ratio of 80:20 or CrMnPt preferably with an atomic part ratio of 40:50:10. All of these materials have a Néel temperature which lies substantially above room temperature whereby the stability of the magnetic bias is ensured. The ferromagnetic or ferrimagnetic second layer can be composed, for example of Fe, Co, Ni or an alloy of these metals, especially of a soft magnetic alloy like NiFe (permalloy) or an alloy of these metals with other elements, like for example FeAlSi or of a metallic metal oxide. On the combination of first and second layers, a suitable protective layer can additionally be applied, for example of SiC or DLC (diamond like carbon).

[0014] It is especially advantageous when the spatial distribution of the magnetic bias does not correspond to a targeted structured pattern, but rather is randomly generated. Thus the possibility of an unauthorized reproduction of the structure is significantly limited by the complexity of the spatial arrangement of the regions with magnetic bias.

[0015] The distribution of the magnetic bias can be of a one-dimensional form, for example, in the form of a magnetic strip, or can however be in a two-dimensional pattern, i.e. distributed over an area. To improve the signal, a multilayer construction can be provided, i.e. a repetitive sequencing of first layers and second layers.

[0016] With the invention it is advantageous for the magnetic regions to have saturation magnetizations of equal magnitudes. When the coding is subjected to an external magnetic field up to a saturation range, a homogeneous magnetization develops over the extent of the coding which forms a reference and enables a verification test. It will be understood that this is not however a compulsory prerequisite since the saturation magnetization can also vary over the extent of the coding. When these variations are stored, it can be determined via the verification test whether a manipulation has occurred or not. The coding as such is stored in the distribution of the magnetic bias.

[0017] The marking device according to the invention can be produced by forming an antiferromagnetic first layer on a carrier and then applying thereon a ferromagnetic or ferrimagnetic second layer, whereby the first layer and the second layer are so structured that they yield regions with magnetic bias. To the extent that there are regions directly adjacent one another, they should have different magnetic biases coupling in different directions with the second layer. Alternatively, it can be provided that the first layer is limited to spaced regions and the second layer is applied thereto, whereby the second layer can also cover the regions between the regions of the first layer. Then the regions of the first layer can be so constructed that they all have overall regions of identically oriented bias or be biased in at least two directions deviating from one another, coupled with the second layer. As an alternative thereto, it is proposed that the first layer be so formed in at least a part of the region that within a region zones of differently oriented magnetic coupling with the second layer are obtained.

[0018] Since the first layer and the second layer can be configured to be relatively thin so that the described magnetic effects arise, it has been found to be desirable to utilize vapor deposition technology to build up the layer, i.e. to use thermal vapor deposition, sputtering or the like. The first layer can then be built up from an antiferromagnetic material until it attains a thickness at which a stable antiferromagnetic preferred direction and thus a corresponding magnetic coupling with the second layer arises. Below this minimum thickness a magnetic bias is suppressed since the antiferromagnetic first layer has no locally fixed magnetic preferred direction. The magnetic preferred direction of the first layer rotates as a consequence of the coupling with the ferromagnetic layer upon demagnetization of the first layer. As a consequence the overall system has a hysteresis curve which is symmetrical about the zero point of the H axis and by comparison with the ferromagnetic second layer which is more spread.

[0019] According to a further feature of the invention, a protective layer is applied to the second layer, especially by vapor deposition.

[0020] The various ways in which the aforedescribed method can be carried out are described more concretely below. Thus the surface of the carrier can be provided, before the application of the first layer, with zones of different roughness. This is based upon the observation that the roughness of the carrier has a significant effect upon the magnetic coupling of the layers lying thereabove. By a corresponding adjustment of the roughness distribution, a regional magnetic bias condition can be obtained which is characterized by a hysteresis curve shifted about the zero point of the H-axis and regions with characteristic ferromagnetic properties with substantially higher coercivity can be created so that no clear magnetic state in remanence is obtained but rather a magnetization of the corresponding region is possible. The combination of the two regions enables information storage, therefore the coding.

[0021] In the simplest embodiment of the aforedescribed method, the surface of the carrier should have at least one zone with a first roughness and at least one zone of a second roughness. This does not exclude the possibility of providing zones with more than two roughnesses in order to make the coding more complex.

[0022] The method enables the first layer to be uniformly applied over the entire area of the carrier. It is, however, also possible to apply the first layer only regionally and also nonuniformly to the extent the basic features of the invention remain applicable.

[0023] The production of different roughnesses can be obtained in various ways. Thus the surface of the carrier can be smoothed by means of surface treatment and/or roughened, for example, by zone-wide etching, sputtering, ion bombardment, etc. In the latter case, the ion bombardment can be locally effected with the aid of a focused ion beam. As an alternative thereto it is however also possible to carry out the ion bombardment on a large area basis and to generate in the vicinity of the carrier a nonhomogeneous electric charge field which blocks the ions in a zonewise manner so that the ions only reach the carrier at locations where there is no blocking electric charge or an attractive electric charge is provided.

[0024] This can be so carried out, for example, that the carrier itself is nonhomogeneously electrically charged. However, an electrically chargeable underlay can be nonhomogeneously electrically charged and the carrier can be placed on this underlay, whereby the ion bombardment is then effected on the carrier. Advantageously the carrier foil is drawn from a supply and brought together with a continuously moved charging foil. Then they are again separated. In this case, the charging foil can also be drawn from a supply and then charged and after the ion bombardment, can be taken up on a store. Alternatively thereto, it can be provided that the charging foil is displaced in an endless path through an ion bombardment station and the charging foil can be charged upstream of the ion bombardment station and discharged downstream of the ion bombardment station or the electrical charge can be homogenized. In addition or in combination therewith it is possible to coat the surface of the carrier zonewise or to provide the surface of the carrier zonewise with different roughness coatings. This can be done by means of printing, lithography or vapor deposition, for example, sputtering.

[0025] To the extent zones with different roughnesses are generated by coating, the method according to the invention can provide the displacement of a carrier foil and a masking foil continuously from respective supplies from which they are drawn and then brought together and the application of the coating from the side of the masking foil, whereupon the masking foil is again separated from the carrier foil and the latter then provided with the first layer. In this case, the masking foil can be provided already before it is introduced into the supply with openings. Alternatively it is however possible to equip the masking foil with openings first after it has been withdrawn from the supply and before it is brought together with the carrier foil, for example with the aid of a cutting laser. The aforedescribed method with the aid of a masking foil can also be used for the ion bombardment to limit the surface-wise ion bombardment to zones of the carrier through the openings in the masking foil.

[0026] The aforedescribed method can be carried out with an apparatus which is characterized by:

[0027] a) a supply store for a carrier foil;

[0028] b) a supply store for a masking foil;

[0029] c) a surface treatment station for treating the carrier foil;

[0030] d) a receiving store for the take-up of the masking foil;

[0031] e) a receiving store for the take-up of the carrier foil;

[0032] f) guide devices and a drive for feeding the carrier foil from the supply store through the surface-treatment station up to the receiving store and for bringing together the carrier foil and the masking foil but upstream of the surface-treatment station and for separating the carrier foil and masking foil downstream of the surface-treatment station.

[0033] With the aid of this device, a correspondingly treated carrier foil and be produced which is then removed from this device and introduced into a device for applying the first layer and the second layer, whereby in this device then corresponding coating stations are provided. It can however be advantageous for the surface treatment of the foil and its coating to be carried out in a single device in which the aforedescribed device is completed with the following apparatus parts:

[0034] a) a first coating station for applying the first layer to the carrier foil;

[0035] b) a second coating station for applying the second layer;

[0036] c) a receiving store for the take-up of the marking device;

[0037] d) guide units and a drive for feeding the carrier foil from the supply store through the surface-treatment station and the coating stations to the receiving store and for bringing together the carrier foil and the masking foil upstream of the surface-treatment station and for separating the carrier foil and masking foil upstream of the first coating station.

[0038] The coating stations are then provided with devices for producing a sufficiently strong magnetic field that they are suitable to establish the directions of the magnetic bias. The devices are so configured that directly above the carrier foil, between the coating stations and the carrier foil and at the location that the material meets the carrier foil, the magnetic field has a magnitude sufficient to establish the direction of the magnetic bias.

[0039] The apparatus according to the invention enables a rapid and economical production of the marking device, whereby the carrier foil can then be packaged depending upon the respective use purpose. The surface-treatment station and the coating station can also be assembled together to a station with multiple treatment units and/or coating units.

[0040] To the extent that the masking foil initially has no openings, between the supply store for the masking foil and the junction of the masking foil and the carrier foil, a mask-forming station is arranged for producing the openings in the masking foil whereby the mask-forming station preferably has a laser-burning device. In this case, a control device should be provided for locally varying the position of the laser-burning device.

[0041] The surface-treatment station can have at least one coating unit, preferably in the form of a vapor-deposition unit or a printing unit. Instead, a device for etching the surface of the carrier foil can also be considered.

[0042] The surface-treatment station can also be constructed with an ion-bombardment station for the ion bombardment of the carrier foil since the roughness of the surface can also be influenced by ion bombardment. The ion-bombardment station can produce a focused ion beam whereby a control device for the targeted control of the ion beam is provided. Such a focused ion beam can be eliminated, i.e. the ion bombardment can be effected over an area when an electrically-chargeable carrier foil is passed through the ion-bombardment station and via the charging device is provided with a nonhomogeneous electric charge. A corresponding arrangement can be also achieved by passing through the ion-bombardment station an electrically-chargeable charging foil which is provided with a nonhomogeneous electric charge and the feed device brings the carrier foil and the charging foil together upstream of the ion-bombardment station. Because of the pattern of the electric charge, the ion beam is blocked where the electric charge corresponds to the charge on the ions so that the ion beam only impinges in those zones of the carrier foil where the carrier foil or the charging foil is without an electric charge or has an opposite electric charge.

[0043] In carrying out the aforementioned proposal, a supply store for the charging foil can be provided upstream of the ion-bombardment station and a receiving store can be provided downstream of the ion-bombardment station while a charging device is provided between the supply station and the ion-bombardment station for applying an electric charge pattern. Alternatively, however, it is also possible to form a charging foil as an endless foil and via the guide devices to feed it together with the carrier foil through the ion-bombardment station, whereby a charging device is provided in the travel direction upstream of the ion-bombardment station and a quenching device is provided for quenching the charge or homogenizing the charge between the ion-bombardment station and the charging device. In this embodiment, the charging foil is discharged after traveling through the ion-bombardment station continuously or is provided with a homogeneous charge and is then returned anew to be written with the pattern whereby each writing can be carried out individually.

[0044] The charging foil can be fed over a plurality of rerouting rollers. It is however also possible to stretch the charging foil on a support roll which is juxtaposed with the ion-bombardment station. Instead of a foil, the roll periphery itself can be electrically chargeable, for example, by a correspondingly formed coating. Then a quenching device and a writing device should be located one after the other in the direction of rotation of the support roll and in the vicinity of the roll periphery which is free from the carrier foil.

[0045] According to a further feature of the invention, an additional coating station is provided to apply a protective layer on the second layer. The coating station is preferably vapor-deposition units with which very thin layers can be produced. For vapor deposition, especially thermal vapor deposition or sputtering are to be considered.

[0046] The supply store or the supply stores and the receiving store or receiving stores are advantageously formed supply chambers or storage rolls. In the coating stations and also in the surface-treatment stations, carrier rollers can be arranged over the roller peripheries of which the carrier foil is guided so that an effective treatment is possible.

[0047] A further fabrication method resides in that at least the first layer, in the layer buildup, is subjected to

[0048] a) a nonhomogeneous magnetic field or

[0049] b) a homogeneous magnetic field and nonhomogeneous temperature field or

[0050] c) a nonhomogeneous magnetic field and a nonhomogeneous temperature field.

[0051] The distribution of this field creates a pattern of different magnetic properties and allows the first layer to be formed with a uniform layer thickness. Preferably the second layer is also provided under such field since thereby the pattern of the different magnetic characteristics and hence the coding is seen clearer. In this case the magnetic field distribution and/or the temperature distribution should be held invariable during the buildup of the two layers.

[0052] A magnetic field can for example, be produced in that a magnetizable carrier or a magnetizable underlay for the carrier is nonhomogeneously or homogeneously magnetized. In the latter case, the carrier is placed on this underlay and at least the buildup of the first layer is carried out on the combination of underlay and carrier. It will be understood that the second layer as well can be applied in the presence of such carrier or such underlay.

[0053] The marking device can be fabricated especially economically when a carrier foil is drawn from a supply and is brought together with a continuously moving underlay and both are fed through a first coating station in which the first layer is applied. In this case it is possible to separate the carrier foil and underlay already after the first coating station. To the extent that the second layer is also to be applied in the presence of a magnetic field, the carrier foil and the underlay can also be passed through a second coating station where the second layer is applied so that the carrier foil and underlay are first separated downstream thereof.

[0054] According to the invention it is further proposed that the magnet foil be drawn from a supply and then magnetized and that downstream of the first and second coating stations be collected in a store. Instead, the magnetic foil can be provided so that it circulates at least through the first coating station. To the extent that respectively changing nonhomogeneous magnetic fields are to be produced, the invention provides that the magnet foil be magnetized upstream of the first coating station and downstream of the first or second coating station be demagnetized or have its magnetization homogenized.

[0055] Instead of a magnetic foil, the magnetic field can also be built up by magnetic field generating coils whereby both a homogeneous magnetic field or a nonhomogeneous magnetic field can be produced.

[0056] A device for carrying out the aforedescribed method is characterized by

[0057] a) a supply store for a carrier foil;

[0058] b) a first coating station for building up the first layer;

[0059] c) a magnetic field device juxtaposed with at least the first coating station for producing a magnetic field over the area of the carrier foil;

[0060] d) a second coating station for applying the second layer;

[0061] e) a receiving store for taking up the marking device;

[0062] f) guide elements and a drive for feeding the carrier foil from the supply store through the coating stations to the receiving store.

[0063] In this device, the magnetic field unit can be disposed upstream of the first coating station and through it a magnetizable carrier foil can be passed. Instead of this, the magnetic field unit can have a magnet foil which is magnetized nonhomogeneously or homogeneously and the guide element can be effective to bring together the carrier foil and magnet foil upstream of the first coating station. In a more concrete arrangement, this can be achieved in that a supply store for the magnet foil is provided upstream of the first coating station and a receiving store downstream of the first or second coating station and the magnetic field device can have a magnetization unit for magnetizing the magnet foil and it is arranged between the supply store and the first coating station.

[0064] Instead of the latter, however, the magnet foil can have an endless configuration and can be guided by the guide elements together with the carrier foil at least through the first coating station. To the extent that a nonhomogeneous magnetization is provided, the magnet field unit can have a magnetizing device located upstream of the first coating station in the travel direction and which generates a nonhomogeneous magnet field and a quenching device for demagnetization or homogenizing the magnetic field between the first and second coating stations. The magnet foil can be passed freely over rerouting rollers. It can however also be stretched on a support roll which is juxtaposed with the first coating station.

[0065] As an alternative thereto it is proposed that the first coating station be juxtaposed with a support roll over the roll periphery of which the carrier foil is led past the coating station, whereby the roll periphery is magnetizable. To the extent that a nonhomogeneous magnetization is provided, the magnetic field device should have a magnetizing unit for magnetizing the roll periphery whereby a quenching device for demagnetization or homogenizing the magnetization is provided. In this case, the roll periphery can be provided with a magnetizable coating, for example in the form of a polymer layer with magnetic particles incorporated therein. The quenching device and the magnetizing device should be located one after the other in the direction of rotation of the support roll in the region of the roll periphery which is free from the carrier foil. Alternatively, the magnetic field device can be provided with a plurality of magnetic-field generating coils. These coils can be arranged in the vicinity of the surface of a carrier roll over the periphery of which the carrier foil is guided through the coating station so that during the vapor deposition a nonhomogeneous magnetic field prevails. The strength of the magnetic field generated is so selected that it suffices to fix the magnetic bias.

[0066] The same effect as can be accomplished with the magnetic field device can also be achieved by means of heating device for creating a nonhomogeneous temperature field, whereby the heating device can also be combined with a magnetic field device so that both a nonhomogeneous magnetic field and also a nonhomogeneous temperature field can be generated. The heating device can, for example, be provided with a laser unit by means of which the first layer can be locally heated during its buildup.

[0067] The method of the invention can also be carried out such that, upon the application of the first layer, at least one mask is used to cover the regions in which at least temporarily there is to be no first layer buildup. This can be achieved, for example, by the use of a single mask during the formation of the first layer to limit it to certain regions so that the other regions remain first layer free. Instead, however, the method can be so carried out that two layers are deposited on the carrier and one of these layers can be deposited without a mask and another layer regionally with use of a mask, whereby the thicknesses only in the region of superposition of the layers suffices for the formation of a magnetic bias with shifting of the hysteresis cover. In the other regions, a widened symmetrical hysteresis curve arises so that the coding is given by the sequence of these regions. Hence the masks can be used alternatively in the buildup of the first or of the second layer.

[0068] The mode of carrying out the method is also possible in which the formation of the first layer utilizes a first mask regionally in a first position and then in a second position utilizing a second mask covering the first layer, whereby the thicknesses of one of the two layers is so small that in these regions no magnetic bias arises. In this case it is advantageous when the first layer is applied with a differently oriented magnetic field than the second layer so that as a result differently directed magnetic biases will arise.

[0069] So that the marking device can be fabricated in a continuous process, the invention provides that a carrier foil and at least one mask foil are drawn continuously from respective supplies and brought together and that then the coating is effected from the side of the masking foil and the masking foil or foils are then separated from the carrier foil. The masking foil is provided with cutouts which, before and after withdrawal from the supply, the latest however before the masking foil is brought together with the carrier foil, can be formed in the masking foil.

[0070] The device for carrying out the aforedescribed method can be configured similarly to the device which has been proposed above for the zonewise coating of the carrier foil using a masking foil. Deviating from this device, however, the masking foil is fed through the first coating station so that the first layer on the carrier foil is initially formed only in the regions left free from the masking foil. In this case, the first coating station can have at least two coating devices disposed one after the other, whereby the masking foil is fed together with the carrier foil only through one of the coating devices. As a variant thereon, each of the coating devices can have a supply store for a masking foil and a receiving store for taking up the masking foil associated therewith.

[0071] A further fabrication mode is characterized in that the first layer is initially applied on a wide area basis and then a portion of the first layer is regionally removed to such an extent that there no magnetic bias arises. With this method it is possible to apply the first layer initially with a uniform thickness and under a homogeneous magnetic field with the thicknesses so dimensioned that after application of the second layer, a magnetic bias arises. By local ablation of the first layer, regions are formed in which no magnetic bias is effective because the requisite thickness for the magnetic prestress no longer exists or the first layer has there been completely removed.

[0072] In this manner the desired signature (coding) is formed. The ablation can be effected, for example, by means of chemical etching, whereby the regions which are not to be etched are covered by means of a lithographic technique. Instead, an ion sputtering etching or ion etching can be carried out which is especially suitable for a continuous process using a carrier foil.

[0073] The last-mentioned method can be carried out by means of an apparatus which is similar to the apparatus described previously in which the carrier foil is roughened by means of ion bombardment in a zonewise manner. A difference as to this apparatus is the ion bombardment station now located between first and second coating stations in order to regionally remove the first layer. The restriction of the ion bombardment to individual regions can be obtained with the same means as described above, thus for example, by the effect of a focused ion beam or by limiting the effect of an ion beam bombardment over an area, for example, with the aid of a mask, also in the form of a foil, or by impressing a nonhomogeneous electric charge in the region of the carrier. The latter can be done by means of an electrically chargeable carrier foil or with the charge foil already described above and which is brought together with the carrier foil in the region of the ion bombardment station and supplies a corresponding nonhomogeneous electric field that regionally blocks the ion beam so that it in these regions, does not serve to remove the first layer.

[0074] In a further fabrication method, the first layer is galvanically applied and the application is controlled with respect to place and thickness by a nonhomogeneous electric field. This is then so carried out that the metal ions for the first layer are blocked by the electric field regionally and regionally pass, indeed in such form that on the carrier regions with positive and regions with negative electric charge are generated. There where the charge is negative, the positively charged metal ion will be deposited for the purpose of regional buildup of the first layer while they will be blocked in regions of positive charge.

[0075] The aforedescribed method is involved also in the fabrication of the marking device. It is however also possible to produce regions of different magnetic bias first after the creation of the coding. Such a method is characterized in that the coding is heated locally to such a temperature that there the magnetic coupling between first and second layers is altered and indeed preferably in the sense that the magnetic bias is destroyed and the magnetization in these regions has a symmetrical hysteresis curve. As an alternative to the aforementioned method, it can be provided that the coding after manufacture is heated with a homogeneous temperature field to such temperature that the magnetic coupling between first and second layers is altered, especially destroyed and the coding is simultaneously with a nonhomogeneous magnetic field, applied. The latter can be done with a magnet foil as has been described above already in conjunction with the application of a nonhomogeneous magnetic field in the buildup of the first layer.

[0076] The aforedescribed method allows, during fabrication of the coding, a uniform thickness of the first and second layer to be created. It is suitable especially for continuous coating processes. To the extent that a local heating is carried out, this can be done by means of a layer.

[0077] The apparatus for carrying out this method can be configured similarly to the aforedescribed apparatus in which the first layer is regionally removed by means of ion bombardment. Instead of the ion bombardment station, a heating station is now provided for heating the coding between the second coating stations and the receiving store for taking up the marking device. The heating station can be provided with a heating device for local heating of the coding whereby, in addition thereto, still another magnetizing device can be provided. Instead, the heating station or a heating device for homogeneous heating of the coding can have a magnetizing device for producing a nonhomogeneous magnetic field. The magnetization device can be configured exactly in the same manner as has been described in conjunction with the buildup of the first layer using a nonhomogeneous magnetic field.

[0078] A variation of the magnetic coupling can, for example, also be achieved by means of local ion bombardment. This approach to producing a signature is also suitable for continuous manufacturing processes of the aforedescribed type. To the extent that the apparatus is concerned, one need only replace the heating station of the last-described apparatus by an ion bombardment station which is configured in the identical way as in the apparatus where the ion bombardment is effected for regionally removing the first layer.

[0079] The aforedescribed methods and apparatuses for producing the marking device according to the invention can also be combined with one another. The methods and apparatuses will then be somewhat more expensive. With the aid of such combined methods and apparatuses, however, still more complex codings can be produced without the need for random generators such that such codings are unique and imitation is practically impossible.

[0080] The subject of the invention is, moreover, a method of reading out the above described marking devices with the aid of at least one magnetic field sensor. According to the invention, the coding is subjected to at least two reading processes whereby one reading process if effected in a zero field and one reading process is effected in an external magnetic field or the reading processes are effected in different magnetic fields. In the first-mentioned reading process, the stored information of the magnetic regions is locally detected, for example, by reading out the sequence of flux changes arising at the region boundaries. In the second reading process which preferably is carried out under saturation magnetization, the distribution of the saturation magnetization is detected and compared with a predefined reference structure. The sequence of the reading processes does not matter.

[0081] It is further of advantage that for the reading of the marking device according to the invention, conventional magnetic field sensors are suitable, i.e. for example, inductive sensors, magneto-resistive sensors, magneto-optical sensors, Hall-sensors or SQUID-sensors can be used. The local reading can be effected by causing a relative movement between the magnetic field sensor and the marking device and it makes no difference whether only one or both of them are moved. A plurality of magnetic field sensors can also be used to detect the magnetic structure of the marking device in a rest state at a particular location.

[0082] To determine the information stored in the coding, various features of the hysteresis loop can be considered. It is simple to detect the remanence in a zero field or a very small magnetic field. Instead it is however also possible to detect the flux change at the boundary of two regions since with the marking device according to the invention, at the boundary stray fields arise whose distribution in a particular direction forms the coding.

[0083] Finally according to the invention a method is also provided in which at least two reading processes are carried out without an external magnetic field and the coding before a reading process in one direction and before a further reading process in the other direction is magnetized up to saturation.

[0084] The invention is described in greater detail in connection with exemplary embodiments in the drawing. It shows:

[0085]FIG. 1 a plan view of a part of a first marking device with illustration of the hysteresis loops of two magnetic regions and the signal course;

[0086]FIG. 2 a longitudinal section through a marking device according to FIG. 1 with illustration of the signal course without an externally applied magnetic field;

[0087]FIG. 3 a longitudinal section through a marking device according to FIGS. 1 and 2 with illustration of the signal course with saturation magnetization;

[0088]FIG. 4 a longitudinal section through a part of a second marking device in remanence with illustration of the hysteresis loops of two magnetic regions;

[0089]FIG. 5 an illustration of the principles of a marking device with a magnetic field sensor;

[0090]FIG. 6 an illustration of the principles of making a nonhomogeneous magnetic field by means of a magnetized underlay;

[0091]FIG. 7 an apparatus for producing a marking device by buildup of the first and second layers in a nonhomogeneous magnetic field;

[0092]FIG. 8 an apparatus for producing a marking device by means of a masking foil;

[0093]FIG. 9 an apparatus for producing a marking device by means of ion bombardment of the first layer.

[0094] As FIGS. 1 and 2 show, the marking device 1 is configured as a magnetic strip which is applied to a carrier 2. The carrier 2 can be affixed to any optional object which is to be identified by means of the marking device 1.

[0095] The marking device 1 is two layered, whereby the thicknesses of the layers amounts to between several nanometers and several hundred micrometers. The antiferromagnetic first layer 3 is initially applied to the carrier 2 and is comprised of a multiplicity of mutually-adjacent regions, for example designated at 4 or 5, with different directions of the antiferromagnetic preferred axes. On the first layer 3 a ferromagnetic second layer 6 is vapor deposited. The first layer 3 is so configured as a result of the fabrication method described in detail above, that on the interface with the second layer 6 magnetic preferred directions obtain which are illustrated by the arrows. In this case, the preferred directions of two respectively neighboring magnetic regions 4, 5 are opposite one another. By means of the first layer 3, a corresponding preferred direction is also induced in the respective second layer 6, also illustrated by the arrows in FIGS. 1 and 2. As a result a magnetic bias of the second layer, which is manifested in a shifting of the hysteresis loops on the field strength—H—occur and indeed, in the magnetic region 4 is to the left with reference to the magnetization axis M and is to the right in the magnetic region 5.

[0096] Because of the opposite biases of two neighboring magnetic regions 4, 5, magnetic stray fields or flux alterations are produced in remanence at the boundaries between two neighboring magnetic regions 4 and 5 and can produce a signal in an appropriate magnetic field sensor which corresponds to the signal course 9 shown below. The signals, for example, indicated at 10 give, based upon their orientation and spacing, a coding-forming structure when no external magnetic field is applied, i.e. H=O (FIGS. 1 and 2). When an external magnetic field is applied in the saturation range (H>H_(s)), the magnetic moments of the ferromagnetic layer 6 orient themselves in the direction of the external field, i.e. there is in the reading direction a uniform magnetization with the consequence that the signals 10 disappear.

[0097] With the marking device 11 according to FIG. 4, on the carrier 12, spaced-apart antiferromagnetic segments respectively form a first layer which has been, for example, indicated at 13, i.e. form the antiferromagnetic first layer 13 which is not a closed layer as with the marking device 1 according to FIGS. 1 to 3. The ferromagnetic second layer 14 is vapor-deposited thereover and also covers the regions between the antiferromagnetic segments 13 and which there lies directly on the carrier 12.

[0098] In the vicinity of the antiferromagnetic segments 13, there is a magnetic bias because of the unidirectional preferred direction at the interface of the second layer in all regions of the first layer 13, the magnetic bias being symbolized by the left-indicating arrows, and in which there is a shift of the associated hysteresis loop to the right on the field strength axis H. In the regions between two antiferromagnetic segments 13, there is no voltage, i.e. there is here a hysteresis loop 16 which lies symmetrical to the magnetization axis M. In this case the formation of a spatial structure of the remanent magnetization is here associated with the directions of the field which is used for magnetization. If the field is opposite the preferred direction 10 i.e. in this case to the right up to saturation, there is after cutoff of the rotating field, a sequence of differently oriented remanent magnetizations corresponding to the illustrated hysteresis loops 15, 16. If one magnetizes the marking device in the preferred direction of magnetic bias up to saturation, there is also a magnetization of the ferromagnetic regions in the direction of magnetic bias and the signature disappears. This property can be used for a verification test.

[0099] In FIG. 5 the marking device 1 has been shown in a rotated position so that the carrier 2 lies on the upper side and the coding layer 17 is found on the underside. Below it a magnetic field sensor 31 is arranged which has a reading head 32 past which the marking device 1 with the carrier 22 [sic] is displaced in pull-through direction. At the boundary of the differently magnetized regions in the zero field, a stray field is generated which induces a current pulse 33. Via an external current source 34, an additional current is fed into a coil 35 at the reading head 32, whereby an external magnetic field is generated at the locus of detection. The signal which is produced on reading is processed in an amplifier stage 37 and in a further stage 38. If the external current is equal to zero, the stored information can be read. If the current is sufficient to saturate the coding layer 17, the current pulse 33 disappears. A verification test of the coding is thus possible.

[0100] It is especially advantageous when the magnetic field sensor 31 and the coding layer 17 are so matched that the saturation field corresponds to a field strength in which the characteristic of the magnetic field sensor 31 is linear to enable a distinction between saturation of the coding and saturation of the magnetic field sensor 31 to be recognized. A further possibility for overcoming the saturation problem of various magnetic field sensors, for example inductive or magneto-resistive magnetic sensors is to apply the saturation field in a direction which does not correspond to the sensitive region of the magnetic field sensor. It is also advantageous to use a magnetic field sensor which is capable of detecting the local magnetization of the layer (for example a magneto-optical reading device) so that an influence of the external field on the sensitivity of the magnetic field sensor can be excluded.

[0101]FIG. 6 shows a carrier plate 41 on which a magnetic foil 42 is placed. The magnetic foil 1 [sic] is perpendicular to the layer plane in strips, for example, as shown at 43, and in particular, with one strip 43 with a preferred direction downwardly and an adjacent strip 42 with a preferred direction upwardly as symbolized by the arrows. This gives a stray field configuration which has been indicated diagrammatically by the half circles 44. The thus formed stray field is sufficient to establish a magnetic bias.

[0102] The carrier foil 45 is laid upon the magnet foil 42 which produces a magnetic field distribution whose components in the layer plane vary in correspondence with the underlying pattern as shown by the horizontal arrows on the carrier foil. By vapor depositing a suitable material combination (for example NiO/NiFe) on the carrier foil 45, the magnetic field distribution determines the spatial distribution of the magnetic bias and thus the signature of the coding.

[0103]FIG. 7 shows an apparatus 46 in which the system shown in principle in FIG. 6 can be manufactured in a continuous process. The apparatus 46 is contained in a housing not shown in greater detail herein in which a high vacuum prevails.

[0104] The apparatus 46 has two vapor deposition stations 47, 48, each of which has a support roll 49, 50 which in its lower region is flanked by respective deflection rollers 51, 52 or 53, 54.

[0105] The first vapor deposition station 47 is provided above the associated support roll 49 with two vapor deposition devices 55, 56. The support roll 49 is provided along its roll periphery with a magnet layer, for example an approximately 3 mm of thin polymer layers in which a high proportion of ferromagnetic particles are incorporated. Below the support roll 49 and between the associated rerouting rollers 51, 52 a magnetic unit 59 is provided on the left side which has a row of permanent magnets and/or magnetic-field generating spools. These can provide the magnet layer 58 with a certain magnetization pattern which in its simplest form can be seen in FIG. 6. The magnet layer 58 produces, as a consequence of its magnetization, a corresponding nonhomogeneous magnetic field. At the right adjacent the magnetization device 59, a quenching unit 60 is arranged which either completely demagnetizes the magnetic layer 58 or magnetizes it homogeneously and thus eliminates the nonhomogeneous magnetization previously applied by the magnetization device 59.

[0106] On a supply roll 61, the carrier foil 62, for example a polyester foil, has been rolled up. In operation, the carrier foil, by driving the support roll 49, 50, is withdrawn from the supply roll 61, loops around the first rerouting roller 51 and passes onto the magnetic layer 58 where it is entrained by the rotation of the support roll 49. In the first vapor deposition device, a first layer 63 is applied to the carrier foil 62 of antiferromagnetic NiO and by means of the second vapor deposition device 56, a second layer 64 of ferromagnetic NiFe is applied. By the spatial magnetic field distribution, established by the magnetic layer 58, the desired directional distribution of the magnetic bias is produced.

[0107] After passing around the rerouting rollers 52, 53, the carrier foil 62 passes into the second vapor deposition station 48 where it runs onto the periphery of the associated support roll 50 and rotates with the support roll 50. The foil then passes a vapor deposition device 65 which applies over the entire area a protective layer 66 of, for example, DLC (diamond-like carbon) or SiC. After traversing the second vapor deposition station 48, the carrier foil 62 loops around the last rerouting roller 54 and is taken up by a storage roll 67. It can then be subdivided.

[0108] In the device 71 of FIG. 8 another fabrication method is used. The device 71 has a first vapor deposition station 72, 73 and a second vapor deposition station 74, whereby the vapor deposition stations 72, 73, 74 have support rolls 75, 76, 77 which are flanked in their layer region by respective rerouting rollers 78, 79 or 80, 81 or 82 83. Above the first and third support rolls 75, 77 are respective vapor deposition devices 84, 85. The middle support roll 76 is juxtaposed with two vapor deposition devices 86, 87 disposed one after the other in the peripheral direction.

[0109] Upstream of the first support roll 75 there is a supply roll 88 on which the carrier foil 89 is rolled up. Above the supply roll 88 is a further supply roll 90 on which a masking foil 92 is rolled up. The further supply roll 90 is associated with a laser unit 92 with the aid of which cutouts—for example indicated at 93—are burned out of the masking foil 91.

[0110] In operation, the carrier foil 89 and the masking foil 91 are drawn with the same speed from their supply rolls 88 or 89, for example, by driving the support rolls 75, 76, 77. As a result, in the masking foil 99, shortly downstream of the supply roll 90, a pattern of cutouts 93 are burned into the masking foil with the aid of the laser unit 92. By corresponding control of the laser beam produced by the laser device 92, there can also be a plurality of them, a predetermined or, for example, a continuously changing random pattern as produced by a random generator, can be formed.

[0111] The carrier foil 89 and the masking foil 91 travel on the first rerouting roller 78 together and are entrained by the support roll 75. The masking foil 91 lies to the outside of the carrier foil 89 and against the latter. Both are passed along the upper region support roll 75 past the first vapor deposition unit 84 which deposits a first ferromagnetic layer 94 only in the regions of the cutouts 93 on the carrier foil 89. After passing around the rerouting roller 79, the masking foil 91 is guided away from the carrier foil 89 upwardly and is rolled up on a storage roll 95. The carrier foil 89 travels then horizontally to the next rerouting roller 80 and then loops around the support roll 76 there. With the aid of the vapor deposition unit 86, a second ferromagnetic layer 96 is applied over the entire area to the carrier foil 89. The layer thickness lies below that which is required for a magnetic bias. In the regions corresponding to the cutouts 93 in the masking foil 91, where there is already a first layer 94, the thicknesses of the first and second layers 94 and 96 add to a thickness which lies above the minimum required layer thickness for the magnetic bias.

[0112] With the aid of the second vapor deposition unit 87, a ferromagnetic second layer 97 is applied over the entire area. This forms together with the antiferromagnetic layers 94, 96, a system of first and second layers 94, 96, 97 which in regions of the cutouts 93 has a magnetic bias in the direction of the applied magnetic field which, during the vapor deposition by the vapor deposition unit 84, 86, 87 is produced over the carrier foil 89 by suitable permanent magnets or electromagnets. In the regions which did not correspond to cutouts 93 and were thus kept free in the first vapor deposition, the antiferromagnetic layer 94, 96 does not have the requisite thickness so that there a nonbiased hysteresis curve symmetrical to the zero point of the H-axis prevails.

[0113] Next the thus coated carrier foil 89 loops around the rerouting rollers 81, 82 and passes onto the last support roll 77. With the aid of the further vapor deposition unit 85 there provided, a support layer 98 is applied to the ferromagnetic second layer 97. After passing the last rerouting roller, the carrier foil 89 provided with the coating layer is rolled up on a storage roll 99. It can then be packaged in accordance with the use.

[0114]FIG. 9 shows a further apparatus 111 for producing a marking device with magnetic bias applied regionally. It has in the sequence in the direction of travel a first vapor deposition station 112, an ion bombardment station 113 and a second vapor deposition station 114. The stations 112, 113 and 114 have support rolls 115, 116, 117 which are respectively flanked in their lower regions by two rerouting rollers 118, 119 or 120, 121 or 122, 123.

[0115] The first vapor deposition station 112 is provided with a vapor deposition unit 124 above the support roll 115. The second vapor deposition station 114 has in its upper region two vapor deposition units 125 and 126 disposed one after the other in the peripheral direction of the support roll 117. In the ion bombardment station 113, above the respective support roll 116, an ion bombardment unit 127 is arranged. Below the support roll 116 and between the associated rerouting rolls 120 121 is a charge distributor 128 disposed at the left side and with which the support roll 116 can be provided with regions with positive charge and/or regions with negative charge. This can be achieved for example in accordance with the principles of a laser printer. For this purpose, the support roll 116 is provided with an electrically-chargeable coating 129. To the right of the charge distribution device 128, a quenching device 130 is arranged which can either completely discharge the support roll 116 or provide it with a homogeneous electrical charge.

[0116] On a supply roll 131 a carrier foil 32 is rolled up. In operation, the carrier foil 132 drawn from the supply roll 131 by driving the support rolls 115, 116 117, the carrier foils passing around the first rerouting roller 118 and onto the periphery of the first support roll 115 with which it is entrained. Then the carrier foil travels past the first vapor deposition device 124 and is there provided by sputtering under a homogeneous magnetic field with an antiferromagnetic first layer 133 which has a layer thickness which suffices for effective magnetic bias. With this first layer 133 the carrier foil 132 loops around the following rerouting rollers 119, 120 and passes onto the periphery of the second support roll 116 and loops about the later. It thus travels past the ion bombardment unit 127 which fires upon the first layer 133 over the entire width of the carrier foil 132. Because of the charge distribution on the surface of the support roll 116, which has been provided previously by the charge distributing device 128, there are formed on the surface of the first layer 133 regions of blocking and attracting potential for the ions of the ion bombardment device 127. In the regions with attracting potential, the first layer 133 is ablated to a thickness which lies below that which is required to effectively maintain a magnetic bias.

[0117] The support roll 116 is homogenized as it passes the quenching device 130 upstream of the charge-distribution unit 128, i.e. is either completely discharge or provided with a homogeneous charge so that the charge distribution device 128 always charges the support roll 116 with a new randomly generated distribution pattern.

[0118] After passing around the rerouting rolls 121, 122, the carrier foil 132 arrives at the second vapor deposition station 114 in which it again is fed around the periphery of the support roll 117. There the first layer 133 is coated over its entire area with the aid of the vapor deposition unit 125 with a second layer 134 of ferromagnetic material under a homogeneous magnetic field, the second layer having a suitable thickness and orientation. In the regions in which the first layer has not been ablated by ion bombardment, there arises a magnetic bias with a shift of the hysteresis curve.

[0119] In the further vapor deposition unit 126, the second layer 134 is provided with a protective layer 135. The carrier foil 132 then loops around the last rerouting roller 123 and is rolled up on a storage roll 136. It can then be subdivided into individual pieces.

[0120] It will be self-understood that also in FIGS. 8 and 9, the devices 71 and 111 are within a housing which is under high vacuum. 

1. A marking device (1, 11) for the identification of objects with a coding of regions (4, 5, 13) with different magnetic characteristics, characterized in that magnetic regions (4, 5, 13) are so magnetically biased that their hysteresis loops (7 8, 15) are shifted on the field strength axis (H) relative to a symmetrical pattern on the magnetization axis (M).
 2. The marking device according to claim 1, characterized in that the regions (13) with magnetic bias are spaced apart.
 3. The marking device as defined in claim 2, characterized in that regions with magnetic bias (13) have such magnetic hysteresis that they are not magnetically biased.
 4. The marking device according to one of claims 1 to 3, characterized in that the regions (4, 5, 13) with magnetic bias have differently shifted hysteresis loops and/or different preferred directions of the magnetic bias.
 5. The marking device according to claim 4, characterized in that the regions (4, 5, 13) with magnetic bias have different remanences.
 6. The marking device according to claim 4 or 5, characterized in that the regions (4, 5,) with magnetic bias border one another and the respective neighboring regions have differently shifted hysteresis loops and/or different preferred directions.
 7. The marking device according to one of claims 1 to 6, characterized in that the regions (4, 5, 13) with magnetic bias have at last one antiferromagnetic first layer (3, 13) and at least one ferromagnetic or ferrimagnetic, especially soft magnetic, second layer (6, 14) over the first layer.
 8. The marking device according to claim 4 or 5 and 7, characterized in that the first layer (3) extends over a plurality of regions (4, 5) bounding one another with magnetic bias.
 9. The marking device according to at least claims 2, 3 and 7, characterized in that the second layer (14) also extends over the regions between the regions (13) with magnetic bias.
 10. The marking device according to one of claims 1 to 9, characterized in that the first layer (3, 13) is comprised of an intrinsically antiferromagnetic material.
 11. The marking device according to one of claims 1 to 10, characterized in that the first layer (3, 13) is so assembled from superimposed ferromagnetic partial layers that they couple in a nonparallel, especially antiparallel manner.
 12. The marking device according to one of claims 1 to 11, characterized in that the second layer (64, 97, 134) is covered with a protective layer (66, 98, 135).
 13. A method of making a marking device according to one of claims 1 to 12, characterized in that an antiferromagnetic layer (3, 13, 62,94, 96, 133) is formed on a carrier (2, 12, 62, 89, 132) and that a ferromagnetic or ferrimagnetic second layer (6, 144, 65, 97, 134) is applied to the first layer and that by the effect of a magnetic field, regions (4, 5, 13) with magnetic bias are produced.
 14. The method according to claim 13, characterized in that spaced-apart regions of an antiferromagnetic first layer (13) are formed on a carrier (12) and a ferromagnetic or ferrimagnetic second layer (14) is applied thereon.
 15. The method according to claim 14, characterized in that the second layer (14) is also applied over the regions between the first layer (13).
 16. The method according to claim 14 or 15, characterized in that the regions of the first layer are so formed that they couple with the second layer in at least two mutually deviating directions.
 17. The method according to claim 14 or 15, characterized in that the first layer in at least a part of the regions is so configured that within a region there are zones of differently directed magnetic coupling with the second layer.
 18. The method according to one of claims 13 to 17, characterized in that the first and second layers (3, 13, 63, 94, 96, 133; 6, 14, 65, 97, 134) are applied by vapor deposition.
 19. The method according to claim 13 to 18, characterized in that a protective layer (66, 98, 135) is applied on the second layer (6, 14, 565.134) especially by vapor deposition.
 20. The method according to claim 13 to 19, characterized in that the surface of the carrier, prior to the application of the first layer, is provided with zones of different roughnesses.
 21. The method according to claim 20, characterized in that the surface of the carrier has at least one zone which has a first roughness and at last one zone which has a second roughness.
 22. The method according to claim 20 or 21, characterized in that the first layer and/or the second layer is applied uniformly.
 23. The method according to one of claims 20 to 22, characterized in that the surface of the carrier is coated using lithographic techniques regionally.
 24. The method according to one of claims 20 to 22, characterized in that the surface of the carrier is smoothed and/or roughened zonally by means of surface treatment.
 25. The method according to claim 24, characterized in that the surface of the carrier is zonally roughened by means of etching and/or ion bombardment.
 26. The method according to claim 25, characterized in that the ion bombardment is effected with the aid of a focussed ion beam.
 27. The method according to claim 25, characterized in that the ion bombardment is effected over the surface area and in the vicinity of the carrier a nonhomogeneous electric charge field is generated.
 28. The method according to claim 27, characterized in that an electrically chargeable carrier is electrically charged nonhomogeneously before the ion bombardment.
 29. The method according to claim 27, characterized in that an electrically chargeable underlay is nonhomogeneously electrically charged and that the carrier is placed on its underlay and the ion bombardment of the carrier follows.
 30. The method according to claim 29, characterized in that a carrier foil is drawn from a supply and brought together with a continuously displaced charging foil and the carrier foil is impacted with ion bombardment.
 31. The method according to claim 30, characterized in that a carrier foil and the charging foil are separated after the ion bombardment.
 32. The method according to claim 30 or 31, characterized in that the charging foil is drawn from a supply and then charged and after the ion bombardment is taken up in a store.
 33. The method according to claim 30 or 31, characterized in that the charging foil is fed in a circulating path through an ion bombardment station and the charging foil is charged upstream of the ion bombardment station and downstream of the ion bombardment station is discharged or has its electric charge homogenized.
 34. The method according to one of claims 20 to 22, characterized in that the surface of the carrier is coated zonewise or is provided zonewise with coating of different roughnesses.
 35. The method according to claim 34, characterized in that the surface of the carrier is printed.
 36. The method according to claim 34, characterized in that the surface of the carrier is subjected to vapor deposition zonewise.
 37. The method according to one of claims 25 or 26 or 34 or 35, characterized in that a carrier foil and a masking foil are continuously drawn from respective supplies and fed together and that then the application of the coating or the ion bombardment is effected from the side of the masking foil and that the masking foil is again separated from the carrier foil and this is then provided with the first layer.
 38. The method according to claim 37, characterized in that the masking foil after being withdrawn from the supply and before being brought together with the carrier foil is provided with cutouts.
 39. An apparatus for carrying out the method according to claim 37 or 38, characterized by: a) a supply store for a carrier foil; b) a supply store for a masking foil; c) a surface treatment station for treating the carrier foil; d) a receiving store for the take-up of the masking foil; e) a receiving store for the take-up of the carrier foil; f) guide elements and a drive for feeding the carrier foil from a supply store through the surface treatment station to a receiving store and for feeding the carrier foil and the masking foil together upstream of the surface treatment station and for separating the carrier foil and the masking foil downstream of the surface treatment station.
 40. The apparatus according to claim 39, characterized by: a) a first coating station for applying the first layer to the carrier foil; b) a second coating station for applying the second layer onto the first layer; c) a receiving store for the take-up of the marking device; d) guide elements and a drive for feeding the carrier foil from a supply store through the surface treatment station and the coating stations to the receiving store and for feeding the carrier foil and the masking foil together upstream of the surface treatment station and for separating the carrier foil and masking foil upstream of the first coating station.
 41. The apparatus according to claim 39 or 40, characterized in that the surface treatment stations have a multiplicity of treatment devices disposed one after another and each treatment device has a supply store for a masking foil and a take-up store for receiving the masking foil.
 42. The apparatus according to claims 39 to 41, characterized in that between a supply store for the masking foil and the joining of the masking foil and carrier foil, a mask-forming station for producing cutouts in the masking foil is provided.
 43. The apparatus according to claim 40, characterized in that the mask-forming station has a laser-burning device.
 44. The apparatus according to claim 43, characterized in that the mask-forming station has a control device for the variable positioning control of the laser-burning device. 45 The apparatus according to one of claims 39 to 43, characterized in that the surface-treatment station has at least one coating device.
 46. The apparatus according to claim 45, characterized in that the coating device is configured as a vapor deposition device.
 47. The apparatus according to claim 45, characterized in that the coating device is configured as a printing device.
 48. The apparatus according to one of claims 39 to 44, characterized in that the surface-treatment station is a device for etching the surface of the carrier foil.
 49. The apparatus according to one of claims 39 to 44, characterized in that the surface-treatment station is configured as an ion-bombardment station.
 50. The apparatus for carrying out the method according to one of claims 25 to 33, characterized by: a) a supply store for a carrier foil; b) an ion-bombardment station for the ion-beam impingement of the carrier foil; c) a receiving store for the carrier foil; d) guide elements and a drive for feeding the carrier foil from the supply store through the ion-bombardment station to the receiving store.
 51. The apparatus according to claim 50, characterized by a) a first-coating station for applying the first layer to the carrier foil; b) a second coating station for applying the second layer on the first layer; c) a receiving store for the marking device; d) guide elements and a drive for feeding the carrier foil store a supply store through the ion-bombardment station and the coating stations to the receiving store.
 52. The apparatus according to one of claims 50 or 51, characterized in that the ion-bombardment station produces a focused ion beam and a control device is provided for the targeted control of the ion beam.
 53. The apparatus according to one of claims 50 or 51, characterized in that an electrically-chargeable carrier foil is fed through the ion-bombardment station and is provided with a nonhomogeneous electric charge by a charging device.
 54. The apparatus according to one of claims 50 or 51, characterized in that an electrically-chargeable carrier foil is fed through the ion-bombardment station and is provided with a nonhomogeneous electric charge by a charging device and that the guide elements effect a feeding of the carrier foil and charging foil together upstream of the ion-bombardment station.
 55. The apparatus according to claim 54, characterized in that a supply store is provided for the charging foil upstream of the ion-bombardment station, a receiving store is provided downstream of the ion-bombardment station, and a charging device is provided for the nonhomogeneous charging of the charging foil between the supply store and the ion-bombardment station.
 56. The apparatus according to claim 54, characterized in that the charging foil has an endless configuration and is fed via the guide elements together with the carrier foil through the ion-bombardment station, and in that the charging device is provided upstream of the ion-bombardment station in the travel direction of the carrier foil and a quenching device for discharging or homogenizing the electric charge is provided between the ion-bombardment station and the charging device.
 57. The apparatus according to claim 56, characterized in that the charging foil is stretched over a support roll which is juxtaposed with the ion-bombardment station.
 58. The apparatus according to one of claims 50 or 51, characterized in that the ion-bombardment station is juxtaposed with a support roll over a roll periphery of which the carrier foil traverses the ion-bombardment station and in that the roll periphery is chargeable with an electric charge, whereby the charging device for charging the roll periphery and a quenching device for discharging the roll periphery or homogenizing the electric charge thereon are provided.
 59. The apparatus according to claim 58, characterized in that the roll periphery has a coating which can be charged with an electric charge.
 60. The apparatus according to one of claims 57 to 59, characterized in that the discharge device and the charging device are provided one after the other in the rotation direction of the support roll and in the region of a roll periphery thereof which is free from the carrier foil.
 61. The apparatus according to one of claims 40 to 60, characterized in that a further coating station s provided for applying a protective layer upon the second layer.
 62. The apparatus according to one of claims 40 to 61, characterized in that the coating stations have vapor deposition units.
 63. The apparatus according to one of claims 39 to 62, characterized in that the supply store or supply stores and the receiving store or the receiving stores are configured as supply rolls or storage rolls.
 64. The apparatus according to one of claims 40 to 63, characterized in that the surface-treatment station or the ion-bombardment station and the coating station have carrier rolls over whose roll peripheries the carrier foil is fed.
 65. The method according to one of claims 13 to 19, characterized in that at least the first layer (63) is produced by a layer buildup with a) a nonhomogeneous magnetic field or b) a homogeneous magnetic field and nonhomogeneous temperature field or c) a nonhomogeneous magnetic field and a nonhomogeneous temperature field.
 66. The method according to claim 65, characterized in that the second layer is also affected during deposition by a) a nonhomogeneous magnetic field or b) a homogeneous magnetic field and nonhomogeneous temperature field or c) a nonhomogeneous magnetic field and a nonhomogeneous temperature field.
 67. The method according to claim 65 or 66, characterized in that the magnetic field distribution and/or the temperature distribution is maintained during the formation of the first layer and the deposition of the second layer without change.
 68. The method according to one of claims 65 to 67, characterized in that to produce the magnetic field, a magnetizable carrier is magnetized.
 69. The method according to one of claims 65 to 67, characterized in that to produce the magnetic field, a magnetic underlay (58) is magnetized and the carrier (62) is placed on this underlay (58) and at least the formation of the first layer (63) is effected on the combination of the underlay (58) and the carrier (62).
 70. The method according to claim 69, characterized in that the second layer (64) is also applied in the presence of the underlay.
 71. The method according to claim 69 or 70, characterized in that a carrier foil (62) is drawn from a supply (61) and fed together with a continuously moving magnetic foil (68) and both are fed through a first coating station (47) in which the first layer (63) is applied.
 72. The method according to claim 71, characterized in that the carrier foil (62) and magnetic foil (58) are separated downstream of the first coating station (47).
 73. The method according to claim 71, characterized in that the carrier foil and magnetic foil are also fed through a second coating station in which the second layer is applied and that the carrier foil and magnetic foil are then separated.
 74. The method according to one of claims 71 to 73, characterized in that the magnetic foil is withdrawn from a supply and then magnetized and after the first or second coating station is taken up in a store.
 75. The method according to one of claims 71 to 73, characterized in that the magnetic foil (58) is fed in a closed path at least through the first coating station (47).
 76. The method according to claim 75, characterized in that the magnetic foil (58) is magnetized upstream of the first coating station (47) and downstream of the first or second coating station is demagnetized or has its magnetization homogenized.
 77. The method according to one of claims 65 to 68, characterized in that the magnetic field is created with magnetic-field generating coils.
 78. An apparatus for carrying out the method according to one of claims 64 to 77, characterized by: a) a supply store (61) for a carrier foil (62); b) a first coating station (47) for applying the first layer (63); c) a magnetic field device for producing a magnetic field and/or a heating device for producing a temperature field over the area of the carrier foil (62) in the first coating station (63); d) a second coating station (48) for applying the second layer (65) on the first layer (63); e) a receiving store (66) for taking up the marking device; f) guide elements (49 to 54) and a drive for feeding the carrier foil (62) from the supply store (61) through the coating station (47, 48) to the receiving store (66).
 79. The apparatus according to claim 78, characterized in that the magnetic-field device is arranged upstream of the first coating station and through this coating station a magnetizable carrier foil is fed.
 80. The apparatus according to claim 78, characterized in that the magnetic-field device has a magnetic foil (58) which is magnetizable and that the guide elements (49 to 54) effect a meeting of the carrier foil (62) and the magnet foil (58) upstream of the first coating station (47).
 81. The apparatus according to claim 80, characterized in that a supply store is provided for the magnetic foil upstream of the first coating station and a receiving store is provided downstream of the first and second coating station and that the magnetic field device has a magnetization unit which is arranged between the supply store and the first coating station.
 82. The apparatus according to claim 80, characterized in that the magnetic foil (58) has an endless configuration and is fed together with the carrier foil (62) via guide elements (49) at least through the first coating station (47).
 83. The apparatus according to claim 82, characterized in that the magnetic-field device has a magnetizing unit (59) located in the travel direction of the carrier foil (62) upstream of the first coating station (47) which produces a nonhomogeneous magnetic field and that a quenching device (60) for demagnetization or for homogenizing the magnetic field is provided between the first or second coating station (47, 48) and the magnetization unit (59).
 84. The apparatus according to claim 82 or 83, characterized in that the magnetic foil (58) is stretched on a support roll (49) which is homogenized with the first coating station (47).
 85. The apparatus according to claim 78, characterized in that the first coating station has a support roll over a roll periphery of which the carrier foil is fed past the coating station and that the roll periphery is of a magnetizable configuration.
 86. The apparatus according to claim 85, characterized in that the magnetic field device has a magnetizing unit for magnetizing the roll periphery and which produces a nonhomogeneous magnetic field, and that a quenching device for demagnetizing or homogenizing the magnetic field is provided.
 87. The apparatus according to claim 86, characterized in that the roll periphery has a magnetizable coating.
 88. The apparatus according to claim 86 or 87, characterized in that the quenching device and the magnetizing device are provided in the rotation direction of the support roll one after the other in a vicinity of the roll periphery which is free from the carrier foil.
 89. The apparatus according to claim 77, characterized in that the magnetic field unit has a plurality of magnetic field generating coils.
 90. The apparatus according to claim 88, characterized in that the coils are arranged in the region of the surface of a carrier roll, over the roll periphery of which the carrier foil is fed through the coating station.
 91. The apparatus according to one of claims 78 to 90, characterized in that the heating device is configured for the production of a nonhomogeneous temperature field.
 92. The apparatus according to claim 91, characterized in that the heating device is configured as a laser unit.
 93. The apparatus according to claim 78 to 92, characterized in that a further coating station (48) is provided for applying a protective layer (66) to the second layer (64).
 94. The apparatus according to one of claims 78 to 93, characterized in that the coating stations (47, 48) have vapor-deposition units (55,56, 65).
 95. The apparatus according to one of claims 77 to 94, characterized in that the supply store or the supply stores and the receiving store or the receiving stores are configured as supply rolls (61) or storage rolls (67).
 96. The apparatus according to one of claims 77 to 95, characterized in that the coating stations (47, 48) have carrier rolls (49, 50) over whose roll peripheries the carrier foil (62) is fed.
 97. The method according to one of claims 13 to 19, characterized in that at least one mask (91) is used for covering the regions where there is at least temporarily no first layer buildup during the application of the first layer (94, 96).
 98. The method according to claim 97, characterized in that a single mask (91) is used for regional formation of the first layer (94, 96).
 99. The method according to claim 97, characterized in that two layers (94, 96), namely, a layer (96) without a mask and a layer (94) regionally with use of a mask (91) are deposited, whereby the thickness of the first layer is sufficient only in the regions of overlap of the layers (94, 96) for a magnetic bias to be effective.
 100. The method according to claim 97, characterized in that for the deposition of the first layer, a first layer is applied regionally using a first mask and then a second layer is applied using a second mask which covers the first layer, whereby the thickness of on of the two layers is so limited that there no magnetic bias arises or a magnetic bias is produced there which is less than that in the other layer.
 101. The method according to claim 100, characterized in that the first layer is deposited under a magnetic field oriented differently from that under which the second layer is applied.
 102. The method according to one of claims 97 to 101, characterized in that a carrier foil and at least one masking foil (91) are continuously drawn from respective supplies (88, 90) and brought together, and that then a coating is effected from the side of the masking foil (91) and that the masking foil or masking foils (91) are removed from the carrier foil (89).
 103. The method according to claim 102, characterized in that the masking foil (91), after withdrawal from a supply (90) and before being brought together with the carrier foil (89) is provided with cutouts (93).
 104. The apparatus for carrying out the method according to one of claims 97 to 103, characterized by: a) a supply store (88) for a carrier foil (89); b) a first coating station (72, 73) for the layerwise deposition of the first layer (94, 97) on the carrier foil (89); c) at least one supply store (90) for a masking foil (91); d) a second coating station (74) for applying the second layer (97) on the first layer (94, 96); e) a receiving store (95) for the take-up of the masking foil (91); f) a receiving store (99) for the take-up of the masking device; g) guide elements (75 to 83) and a drive for feeding the carrier foil (89) from the supply store (88) through the coating stations (72, 73, 74) to the receiving store (99) and for feeding the carrier foil (89) and the masking foil (91) together in the region of the first coating station (72, 73) and for separating the carrier foil (89) and the masking foil (91) after the application of a layer of the first coating (94, 96) in the first coating station (72, 73).
 105. The apparatus according to claim 104, characterized in that the first coating station (72, 73) has at least two coating devices (84, 86, 87) disposed one after the other and the masking foil (91) together with the carrier foil (89) are fed through only one of the coating devices (84).
 106. The apparatus according to claim 104, characterized in that the first coating station has a plurality of coating units disposed one after the other and each coating device has a supply store for a masking foil and a receiving store for taking up the masking foil.
 107. The apparatus according to one of claims 104 to 106, characterized in that between a supply store (90) for the masking foil and the junction of the masking foil (91) and the carrier foil (89) a mask-forming station (92) for producing cutouts (93) in the masking foil is arranged.
 108. The apparatus according to claim 107, characterized in that the mask-forming station has a laser-burning device (92).
 109. The apparatus according to claim 108, characterized in that the mask-forming station has a control device for varying the position of the laser-burning device (92).
 110. The apparatus according to claim 104 to 109, characterized in that a further coating station (74) is provided for applying a protective layer (98) on the second layer (97).
 111. The apparatus according to one of claims 104 to 110, characterized in that the coating stations have vapor-deposition units (84, 85, 86, 87).
 112. The apparatus according to one of claims 104 to 111, characterized in that the supply store is configured as a supply roll (89, 90) and the receiving store is configured as a storage roll (95, 99).
 113. The apparatus according to one of claims 104 to 112, characterized in that the coating stations (72, 73, 74) have carrier rolls (75, 76, 77) over the roll peripheries of which the carrier foil (89) is fed.
 114. The method according to one of claims 13 to 19, characterized in that the first layer (133) is applied on a wide area basis and then a layer of the first layer (133) is regionally removed to the extent that there no magnetic bias arises.
 115. The method according to claim 114, characterized in that the first layer (133) is applied in a uniform thickness.
 116. The method according to claim 114 or 115, characterized in that the removal is effected by means of etching.
 117. The method according to one of claims 114 to 116, characterized in that for the removal a lithographic process is used.
 118. The method according to claim 114 or 115, characterized in that the removal is effected by means of ion bombardment.
 119. The method according to claim 118, characterized in that the ion bombardment is effected with the aid of a focused ion beam.
 120. The method according to claim 118, characterized in that the ion bombardment (127) is effected on an area-wide basis and in a region of the carrier (132) a nonhomogeneous electric charge field is generated.
 121. The method according to claim 120, characterized in that an electrically-chargeable carrier is electrically charged nonhomogeneously upstream of the ion bombardment.
 122. The method according to claim 120, characterized in that an electrically-chargeable underlay (129) is nonhomogeneously charged and that the carrier (132) is placed on this underlay (129) and the ion bombardment (127) is effected on the carrier (132).
 123. The method according to claim 122, characterized in that a carrier foil is withdrawn from a supply and joined with a continuously moved charging foil as an underlay and both are subjected to ion bombardment.
 124. The method according to claim 123, characterized in that the carrier foil and the charging foil are separated after the ion bombardment.
 125. The method according to claim 123 or 124, characterized in that the charging foil is withdrawn from a supply and that the foil is then electrically charged and after the ion bombardment is taken up in a store.
 126. The method according to claim 123 or 124, characterized in that the charging foil (129) is fed in a closed path through an ion-bombardment station (143) and that the charging foil is electrically charged upstream of the ion-bombardment station (113) and downstream of the ion-bombardment station (113) is discharged or has its electrical charge homogenized.
 127. The method according to claim 118 or 119, characterized in that a carrier foil and a masking foil are continuously withdrawn from respective supplies, and are brought together and that then the ion bombardment is effected from the side of the masking foil and the masking foil is again separated from the carrier foil and this is then provided with the second layer.
 128. The method according to claim 127, characterized in that the masking foil after withdrawal from the supply and before being brought together with the carrier foil is provided with cutouts.
 129. The apparatus for carrying out the method according to one of claims 114 to 128, characterized by: a) a supply store (131) for carrier foil (132); b) a first coating station (112) for the application of the first layer (133) on the carrier foil (132); c) an ion-bombardment station (113) for the regional application of the ion beam to the first layer (133); d) a second coating station (114) for the application of the second layer (135) to the first layer (133); e) a take-up store (136) for the marking device; f) guide elements (115 to 123) and drive for feeding the carrier foil (132) from the supply store (131) through the first coating station (112), the ion-bombardment station (113) and the second coating station (114) up to the receiving store (136).
 130. The apparatus according to claim 129, characterized in that the ion-bombardment station produces a focused ion beam and a control device is provided for the targeted control of the ion beam.
 131. The apparatus according to claim 129 or 130, characterized in that an electrically-chargeable carrier foil is fed through the ion-bombardment station which is provided with a nonhomogeneous electric charge by a charging device.
 132. The apparatus according to claim 129 or 130, characterized in that the ion-bombardment station (113) has an electrically-chargeable charging foil (129) fed through it and which is provided with a nonhomogeneous electric charge and in that the guide elements (116, 120) effect a meeting of the carrier foil (132) and the charging foil (129) upstream of the ion-bombardment station (113).
 133. The apparatus according to claim 132, characterized in that a supply store for the charging foil is provided upstream of the ion-bombardment station and a receiving store is provided downstream of the ion-bombardment station and a charging device for the nonhomogeneous charging of the charging foil is provided between the supply store and the ion-bombardment station.
 134. Apparatus according to claim 132 characterized in that the charging foil (129) has an endless configuration and is fed by the feed elements (116, 120, 121) together with the carrier foil (132) through the ion-bombardment station (113) and in that a charging device (128) is provided in the travel direction of the carrier foil (132) upstream of the ion-bombardment station (113) and a quenching device (130) is provided downstream of the ion-bombardment station for the discharging of the electric charge or homogenization of the electric charge.
 135. The apparatus according to claim 132, characterized in that the charging foil (129) is stretched over a support roll (116) which is juxtaposed with the ion-bombardment station (113).
 136. The apparatus according to claim 129 or 130, characterized in that the ion-bombardment station (113) is juxtaposed with a support roll (116) over the roll periphery (129) of which the carrier foil (132) is fed past the ion-bombardment station (113) and in that the roll periphery (129) is electrically-chargeable, whereby a charging device (128) is provided for charging the roll periphery (129) and a quenching device (130) is provided for discharging or homogenizing the electric charge.
 137. The apparatus according to claim 136, characterized in that the roll periphery has an electrically chargeable coating (129).
 138. The apparatus according to claim 134 to 136, characterized in that the quenching device (130) and the charging device (128) are provided in the direction of rotation of the support roll (116) after one another in a region of the roll periphery which is free from the carrier foil (132).
 139. The apparatus according to claim 129 or 130, characterized in that the masking foil is fed through the ion-bombardment station and the guide elements effect a meeting of the carrier foil and masking foil upstream of the ion-bombardment station in such manner that the ion bombardment is effected from the side of the masking foil and in that the guide elements separate the carrier foil and masking foil downstream of the ion-bombardment station.
 140. The apparatus according to claim 139, characterized in that between a supply store for the masking foil and the meeting of the masking foil and the carrier foil a mask-forming station is arranged for producing cutouts in the masking foil.
 141. The apparatus according to claim 140, characterized in that the mask-formation station has a laser-burning device.
 142. The apparatus according to claim 141, characterized in that the mask-formation station has a control device for varying the position of the laser-burning device.
 143. The apparatus according to one of claims 129 to 142, characterized in that a further coating station (114) is provided for applying a protective layer (135) to the second layer (134).
 144. The apparatus according to one of claims 129 to 143, characterized in that the coating station have vapor-deposition devices (124, 125, 126).
 145. The apparatus according to one of claims 129 to 144, characterized in that the supply store is configured as a supply roll (131) and the receiving store as a storage roll (136).
 146. The apparatus according to one of claims 129 to 145, characterized in that the coating stations (112, 114) and the ion-bombardment station (113) have carrier rolls (115, 116, 117) over the peripheries of which the carrier foil (132) is fed.
 147. The method according to one of claims 13 to 19, characterized in that the first layer is applied galvanically and the application is controlled as to location and thickness by a nonhomogeneous electric field.
 148. The method according to claim 147, characterized in that in the galvanic application regions, a positive and/or regions with negative electrical charges are produced.
 149. The method according to one of claims 13 to 19, characterized in that initially first and second layers are formed over the surface with uniform magnetic bias and then the combination of first and second layers is locally heated to such temperature that there the magnetic coupling between the first and second layers is altered.
 150. The method according to claim 149, characterized in that the heating is effected in a homogeneous magnetic field.
 151. The method according to one of claims 13 to 19, characterized in that the first and second layers are heated by a homogeneous temperature field with such a temperature that the magnetic coupling between the first and second layers is altered and simultaneously a nonhomogeneous magnetic field is applied.
 152. The method according to one of claims 149 to 151, characterized in that the layers are heated to such a temperature that in the effective regions of this temperature the magnetic bias is destroyed.
 153. The method according to one of claims 149 to 152, characterized in that uniform thickness first and second layers are formed.
 154. The apparatus for carrying out the method according to one of claims 146 to 150, characterized by: a) a supply store for a carrier foil; b) a heating station for heating the first and second layers; c) a receiving store for the take-up of the marking device; d) guide elements and a drive for feeding the carrier foil from the supply store through the heating station to the receiving store.
 155. The apparatus according to claim 154, characterized by: a) a first coating station for applying the first layer to the carrier foil; b) a second coating station for applying the second layer on the first layer; c) coating elements and a drive for feeding the carrier foil from the supply store through the coating stations and through the heating station to the receiving store.
 156. The apparatus according to claim 154 or 155, characterized in that the heating station has heating elements for locally heating the first and second layer.
 157. The apparatus according to claim 156, characterized in that the heating station has at last one laser.
 158. The apparatus according to one of claims 154 to 157, characterized in that the heating station has a magnetizing unit for subjecting the first and second layers to a homogeneous magnetic field.
 159. The apparatus according to claim 154, characterized in that the heating station has a heating unit for homogeneously heating the first and second layers and a magnetizing unit for generating a nonhomogeneous magnetic field.
 160. The apparatus according to claim 154 to 159, characterized in that a further coating station is provided for applying a protective layer to the second layer.
 161. The apparatus according to one of claims 155 to 160, characterized in that the coating stations have vapor deposition units.
 162. The apparatus according to one of claims 154 to 161, characterized in that the supply store is configured as a supply roll and the receiving store has a storage roll.
 163. The apparatus according to one of claims 155 to 162, characterized in that the coating stations have carrier rolls over the roll peripheries of which the carrier foil is fed.
 164. The method according to one of claims 13 to 19, characterized in that initially first and second layers are deposited with a uniform magnetic bias over the area and then the first and second layers are locally so subjected to ion bombardment that there the magnetic bias is altered.
 165. The method according to claim 164, characterized in that the first and second layers are locally so subjected to ion bombardment that there the magnetic bias is extinguished.
 166. The method according to claim 164 or 165, characterized in that a uniformly thick first and second layer is deposited with a thickness which is sufficient for a magnetic bias to be effected.
 167. The method according to one of claims 164 to 166, characterized in that the ion bombardment is effected with the aid of a focused ion beam.
 168. The method according to one of claims 164 to 166, characterized in that the ion bombardment is effected over an area and in regions of the carrier a nonhomogeneous electric charge field is produced.
 169. The method according to claim 168, characterized in that an electrically chargeable carrier is nonhomogeneously electrically charged before the ion bombardment.
 170. The method according to claim 168, characterized in that an electrically chargeable underlay is nonhomogeneously electrically charged and that the carrier is placed on this underlay and the ion bombardment is effected on the combination of the underlay and carrier.
 171. The method according to claim 170, characterized in that a carrier foil is drawn from a supply and after the coating is brought together with a continuously displaced charging foil as an underlay and both are subjected to the ion bombardment.
 172. The method according to claim 171, characterized in that the carrier foil and the charging foil are separated after the ion bombardment.
 173. The method according to claim 171 or 172, characterized in that the charging foil is drawn from a supply and then charged and after the ion bombardment is taken up in a store.
 174. The method according to claim 171 or 172, characterized in that a charging foil as an underlay is passed in a closed path through an ion-bombardment station and the charging foil is charged upstream of the ion-bombardment station and downstream of the ion-bombardment station is discharged or has its electric charge homogenized.
 175. The method according to one of claims 164 to 168, characterized in that a carrier foil and a masking foil are continuously drawn from respective supplies and brought together and that the ion bombardment is then effected from the side of the masking foil and the masking foil is again separated from the carrier foil.
 176. The apparatus according to claim 175, characterized in that the masking foil after withdrawal from the supply and prior to being brought together with the carrier foil is provided with cutouts.
 177. The apparatus for carrying out the method according to one of claims 164 to 176, characterized by: a) a supply store for a carrier foil; b) an ion-bombardment station for the regionwise ion beam impingement on the first and second layers; c) a receiving store for the marking device; d) guide elements and a drive for feeding the carrier foil from the supply store through the ion-bombardment station to the receiving store.
 178. The apparatus according to claim 177, characterized by: a) a first coating station for applying the first layer to the carrier foil; b) a second coating station for applying the second layer on the first layer; c) guide elements and a drive for feeding the carrier foil from the supply store through the coating stations and the ion-bombardment station to the receiving store.
 179. The apparatus according to claim 177 or 178, characterized in that the ion-bombardment station produces a focused ion beam and a control device is provided for the targeted control of the ion beam.
 180. The apparatus according to claim 177 or 178, characterized in that an electrically-chargeable carrier foil is fed through the ion-bombardment station and is provided via a charging device with a nonhomogeneous electric charge.
 181. The apparatus according to claim 177 or 178, characterized in that an electrically-chargeable charging foil is fed through the ion-bombardment station and is provided with a nonhomogeneous electric charge and in that the guide elements effect a joining of the carrier foil and the charging foil upstream of the ion-bombardment station.
 182. The apparatus according to claim 181, characterized in that a supply store is provided for the charging foil upstream of the ion bombardment station and a receiving store is provided downstream of the ion-bombardment station and a charging device for the nonhomogeneous charging of the charging foil is provided between the supply store and the ion-bombardment station.
 183. The apparatus according to claim 181, characterized in that the charging foil has an endless configuration and is passed over the guide elements together with the charging foil through the ion-bombardment station and that the charging device is provided in the travel direction of the carrier foil upstream of the ion-bombardment station and a quenching device for discharging or homogenizing the electric charge is provided between the ion-bombardment station and the charging device.
 184. The apparatus according to claim 183, characterized in that the charging foil is stretched over a support roll which is juxtaposed with the ion-bombardment station.
 185. The apparatus according to claim 177 or 178, characterized in that the ion-bombardment station is juxtaposed with a support roll over the roll periphery of which the carrier foil is guided past the ion-bombardment station and in that the roll periphery is chargeable with an electric charge whereby a charging unit for the nonhomogeneous charging of the roll periphery and a discharging device for discharging or homogenizing the electric charge of the roll periphery is provided.
 186. The apparatus according to claim 185, characterized in that the roll periphery has a coating chargeable with an electric charge.
 187. The apparatus according to one of claims 183 to 186, characterized in that the discharging device and the charging device are provided one after the other in the direction of rotation of the support roll in a region of the roll periphery which is free from the carrier roll.
 188. The apparatus according to claim 177 or 178, characterized in that a masking foil is passed through the ion-bombardment station and in that the guide elements effect a joining of the carrier foil and masking foil upstream of the ion-bombardment station in such manner that the ion bombardment is effected from the side of the masking foil and in that the guide elements separate the carrier foil and masking foil downstream of the ion-bombardment station.
 189. The apparatus according to claim 188, characterized in that between a supply store for the masking foil and the joining of the masking foil and the carrier foil, a mask-forming station is arranged for producing cutouts in the masking foil.
 190. The apparatus according to claim 189, characterized in that the mask-forming station has a laser-burning device.
 191. The apparatus according to claim 190, characterized in that the mask-forming station has a control device for variable control of the position of the laser-burning device.
 192. The apparatus according to one of claims 178 to 191, characterized in that a further coating station is provided for applying a protective layer to the second layer.
 193. The apparatus according to one of claims 178 to 192, characterized in that the coating stations have vapor-deposition units.
 194. The apparatus according to one of claims 178 to 193, characterized in that the supply store is configured as a supply roll and the receiving store as a storage roll.
 195. The apparatus according to one of claims 178 to 194, characterized in that the coating stations and the ion-bombardment station have carrier rolls over the roll peripheries of which the carrier foil is guided.
 196. The method of reading a marking device according to one of claims 1 to 12, with the aid of a magnetic field sensor (31), characterized in that the coding is subjected to at least two reading processes whereby one reading process is carried out in a zero field and one reading process is carried out in an external field or the reading processes are carried out under different external magnetic fields.
 197. The method according to claim 196, characterized in that a reading process is carried out under saturation magnetization.
 198. The method for reading marking devices according to one of claims 1 to 12, with the aid of a magnetic field sensor (31), characterized in that at least one reading process is carried out in which the remanence is determined.
 199. The method for reading marking devices according to one of claims 1 to 12, with the aid of a magnetic field sensor (31), characterized in that at least one reading process is so carried out that the flux change at the boundary between two magnetic regions (4, 5, 13, 24, 25) is determined.
 200. The method for reading marking devices according to one of claims 1 to 12, with the aid of a magnetic field sensor (31), characterized in that at least two reading processes are carried out without magnetic fields and that the coding before a readout in one direction and before a further reading process in another direction is magnetized up to saturation. 